Airplane control



May 21, 1940., R. B. Bralslafl.v Er AL AIRPLANE CONTROL 2 Sheets-'Sheet 2 Filed June 25, 19,58

, INVENmR. RE'xBHBiS/S'fand BY FELISBEKEI' A TTORNEY y eect of one of said lateral control instrumentplane speed andperformance and the excessively high [wing loading now ordinarily used, it has rianiltiaizl, y 2,261,7l0

LANE CONTROL Rex E. Beiscl and Paul S. Baker, West ford,

Sonn., assignors to United Aircraft @orporav tion, East Hartford, Conn., a corporation ai ,Delaware l Application June 25, 193s, serial no. nasse 1s claims. (on. 24e) wing naps, to avoid unsafe landing speeds. Such a lift increasing Wing ap 'is particularly illus-e trated and described in Patent No. 2,117,607, issued 4May i7, i938, to R. W. Griswold, H, for Slotted deector nap. Where an airplane is equipped with aileronsv along the trailing edge of the wing, it has not been possible to extend the lift increasing nap for vmore than theportion vof the wing span be tween the ailerons. as the ailerons. occupy a considerable portion of the total wing span it has been possible to obtain only a fraction of the theoretical maximum lift increase by the addition of theliit increasing wing ap. 'While the" lift increase provided by such a iiap between the ailerons is highly benecial, there are some cases in which the amount of llftincrease thus obtained is not suilicientto reduce the landing speed vby the desired amount. Obviously the lift of the wing could be materially improved by inclining or drooping the ailerons at the same time the flap is inclined to thus provide, in elect, a total span lift-increasing iiap.

This invention relates to improvements in airplane controls and has for an object the provision of improved control -means including a plurality o control instrumentalities which may be selectively utilized, either individually or in combination, to control the airplane. y

A further object resides in the provision, in a control meansof the character specied, of an improved changeover mechanism forselectively transferring the control of the airplane from one of a plurality of control instrumentalities to another. .A more specicgobject resides in the provision, in ,an airplane having both ailerons and lift spoilers for lateral control, of manually controllable means for diminishing the controlling 'alities while'simultaneously increasing the controlling eiect of the other.'

Other objects and advantages will be more particularly, .pointed out hereinafter or will become apparent as the description proceeds.

lIn the accompanying'drawings in which like reference numerals are used to designate similar parts throughout there is illustrated a suitable mechanical construction for the purpose of ex' emplifying lthe invention. l The drawings, however, are for the purpose of illustration only and are not to be taken as in any way limiting or restricting the invention as set forth in the appended claims.

In the drawings Fig. lis a diagrammatic perspective view of an airplane ,wing showing a lateral control' arrangement and -control changeover device, constructed according to the invention, applied thereto;

Fig. 2 isa side-elevational view of the changeover mechanism, and,

Fig. 3is an elevational view of the changeover mechanism when rotated 90 degrees from the positionvillustrated in Fig. 2.

Referring to the drawings in detail and particularly'to Fig. 1, the numeral Ill generally indicates an airplane wing having ribs l2 and spars or stiffeners I4 and I6. The. wing is provided witha lift increasing trailing edge ap I8 and has for lateral control the alleronZ and the lift spoiler nap 22 cooperating with a wing slot in a manner well known to the art.

As an incidentto recent improvements in air- The objection to this arrangement has been that whenv the ailerons are sharply inclined or drooped to provide a liftincreasing'eect for the wing they become, to a purposes. As *the maximum efllciency in lateral control is required when the `airplane is Vflying' at very slow speeds it has been found impossible to obtain anything near the maximum theoretical lift increase fromv drooped ailerons while con-` tinuing to use the ailerons as lateral control devices. In Athe construction illustrated this dilculty has been overcome by providing additional ,lateral control devices in the form of lift spoilers which canv be operated independently' ofA the ailerons so that when the ailerons are drooped to increase the lift of the wing the lateral control of the airplane is accomplished by the spoilers. As .the spoilers do not function quite as satisdesirable to use the ailerons for lateral control when the airplane is flying at relatively high speeds and t'o use the spoilers for lateral control mainly when the airplane is lflying at veryv low speeds with the wing flap and ailerons drooped to provide the maximum lift. It is lalso part of the present invention. to especially design the ailerons for use as lateral control devices under high-speed for use as lateral control devices under slow speed conditions.

In order that the lateral control may be .by the ailerons under high-.speed night conditions and become common practice to provide such high performance airplanes with lift increasing devices. -particularly in the nature of lift increasing considerable degree, useless for lateral-control factorily as ailerons at high speeds, it becomes conditions and to specially design the lift spoilers by the spoilers under low-speed flight conditions it becomes necessary to provide some effective means for changing the lateral control from one to the other of these instrumentalities while the airplane is in night.

In the construction illustrated lateral control of the airplane is accomplished by sideways movement of the control column 24 transmitted through the torque tube 26 ofthe lateral control linkage. The aileron 20 is connected by the link 28, the bell crank 30, the link 32, the adjustable fulcrum lever 34 and the link 36 to one side of the device generally indicated at 38. As is more fully described in application Serial No. 212,996, filed June 10, 1938, by Frank C. Albright for Aircraft-control means, the device 34 is operative to droop the ailerons to change their function fr om that of lateral control to that of increasing the lift coefficient of the wing. This device is in the form of a pivoted lever for imparting movement to the links connected thereto in the manner hereinafter described. The opposite aileron is connected by similar elements including the link 40 to the opposite side of the device 38. The spoiler 22 is connected by the link 42, the toggle mechanism generally indicated at 44 and which isdescribed in detail in'application Serial No. 214,486, filed June 18, 1938, by Rex B. Beisel for Airplane control devices, and the links 46, 48 and 58 are connected to the same side of the device 38 as that to which-the aileron 28 is connected. The opposite spoiler is connected to the opposite side of the mechanism by a similar system of links and levers including the link 52. As is clearly illustrated in Fig. 1, the attachment points of the links 36 and 50 to the device 38 are spaced apart along the length of the device and the attachment point of the links 40 and 52 are similarly spaced. The device 38 is pivoted at or adjacent to its center. to a xed portion of the airplane and is inclined in opposite directions upon lateral movement of the control column 24, through a connection with the torque tube 26, which connection includes an arm 54 on the device, an arm 56 connected to the torque tube by a bracket 58, and link 60 connecting the fre'e end of the arms 54 and 56.

From the above description it Will be apparentI that if the connecting points of the links and 52 are opposite the pivotal mounting of the device 38 they will receive no material movement from the device when the device is tilted by lateral movement of the control column while the links 36 and 48 being, as illustrated, remote from the pivotal mounting will receive nearly all of the movement imparted to the device 38 by the operation of the control column. Thus with the position of the parts as illustrated in Fig. 1, the ailerons will be operated to provide lateral control upon sideway movement of the control column 24 but the spoilers will not be operated. If these conditions are reversed so that the links 36 and 40 are at or adjacent to the pivotal mounting and the links 50 and 52 are remote therefrom the movement imparted to the device 38 by the ailerons will not be moved to a material extent. If neither the links 50 and 52 or the links 36 and 40 are near or opposite the pivotal mounting of the device 38 both the spoilers and ailerons will be moved and the controlling effect of each will be determined by the respective distances between their operating links and the axis of the pivotal mounting of the device 38. In changing from one type of control to the other a transitional period occurs in which flight control of the airplane is accomplished by both devices, the contribution of each at any point in the transition from one to the other being approximately directly proportional as to one device and approximately inversely proportional as to the other, to the amount the nuts 84 and 86 are moved from their position at the start of the control transition to the total amount 0f movement necessary to entirely transfer the control function from one device to the other. The control devices and the transfer mechanism are so designed and arranged that, at any point in the transition range the control action, with both control devices in operation, is substantially the same as the control action with only one control device operative, and so that the control power at any point in the transition range is never below a minimum entirely adequate for the control of the airplane. K

The changeover device, generally indicated at 38, is particularly illustrated in Figs. 2 and 3. As illustrated, this device includes a frame comprising a pair of side plates 62 and 64 secured together at their ends by abutments 66 `and 68 and provided at theirmidportions with bearings 10 and 'l2 by which the device is pivotally supported by the axles 'i4 and 16 upon the xed member I8 of the airplane. A screwthreaded shaft 8l) is disposed between the plates 62 and 64 and rotatably supported at its ends in the abutments 66 and 68. This shaft r8i) is rotated by a flexible drive 82 secured at one end to the adjacent end of the shaft 80 and to the abutment 66, and at its opposite end, either directly or indirectly, to a suitable manually controllable operating device. A pair of screw-threaded blocks or nuts 84 and 86 are threaded onto the shaft 88 and spaced apart a distance approximately one-half of the length of the shaft so that when the block 84, for example, is in line with the axis of the axles i4 and 'I6 the block 86 will be at the lower end of the shaft 80 adjacent to the abutment 68, and when the block 86 is in line with the axis of the axles 14 and 16 the block. 84 will be at the upper end of the shaft 80 adjacent to the abutment 66, as indicated in broken lines in Fig. 2. As is particularly illustrated in Fig. 3, the ends of the links 36 and 48 are pivotally connected to the block 86 and the ends of the links 50 and 52 are pivotally connected to the block 84. Preferably the action of the devices 34 and 38 is coordinated in such a manner that the effectiveness of the spoilers is automatically increased as the ailerons are drooped. This may be accomplished by mechanically or otherwise connecting the adjusting screw in member 34 with the adjusting shaft 80 of the changeover device 38 so that as the ailerons are drooped the changeoverdevice is actuated to gradually transfer the lateral control function from the ailerons to the spoilers. l

From this description it will be observed that the lateral control may be changed over from the ailerons tothe spoilers and vice-versa by turning the cable 88 of the flexible drive 82 in the proper direction.

A suitable arrangement for operating they changeover mechanism for coordinating the operation of the changeover mechanism with the operation of other lift increasing and lateral control instrumentalities is particularly illustrated and described in application Serial No. 212,996, filed June 10, 1938, by Frank C. Albright, for Aircraft control means, to which reference may be had for a further description of the construciii of a changeover mechanism for selectively useable control instmmentalities has been illustrated and described for the purpose of disclosing the invention it is to be vunderstood that the invention is ,not limited to the particular construction so illustrated and described but thatV various changes in the sine, shape and arrangement of parts mayv be resorted to and'that a hydraulic or electrically operated mechanism could be used to accomplish the functions of the mechanically operated mechf.*.,=fz. herein illustrated and described without in any way exceeding the scope of the invention.-

Having now described the invention so that others ed in the art may clearly understand they f Patent is as follows. f

.1 is claed is:

l. ln an aircraft ha "n: and selectively useable control instrumentalities associad with Wings T perf() als' 1.6.53 iunction, a single mmually actuatable lcontrol means for operating said instrumentalities, and means for operatively connecting said manually actuntsble means with one or the other of said DSV; ERH'BSS. v

2. in an airplane having a plurality of groups oi"v movable control faces for performing the sae night control function, pilot actuated means for operating both groups of said surfaces,

and pilot controlled group selecting means .for

progressively shifting said flight control function `trom one to another oi said groups of control surfaces while continuously maintaining said yflight control function of said surfaces.

3'. ln an airplane having dierent groups oi movable flight control instrumentalities 'mounted directly on xed parts of said lairplane for performing the same ight control function under diderent ight conditions, means for operating said instrumentalities, and means for renderingv aselected group effective to perform said flight control function and for simultaneously locking the lnstrumentalities of another group in a predetermined position.

4. In an t' lane having wings, two dierent groups of flight control in'strumentalities associated with said wings for performing the same night control function under different respective ight conditions, single manually controllable means for operating both groups of said instrumentallties, and means operative to increase the iiight control effectiveness of one group under the actuation of said manual means and simultaneously decrease the flight control eectlveness oi the other while continuously maintaining` the total flight control eiect substantially unchanged.

5. In an airplane having two different groups of ht control instrumentalities for performing the same flight control function under respectively dierent flight conditions, `means for operating said lnstrumentalities including a .plurality of link members both connected at their ends to a unitary xed fulcrum lever member,

and a manually operable member permanently associated with said lever in the same operative relationship for transferring said flight control function from one of saldgroups of instrumentalities to the other comprising means operable by the air plane pilot during flight for changing the position of the ends of said links with respect to said fulcrum.

decimo what it is desired to secure by Letters v the same ight control control surfaces for use under certain flight conditions and' `a second pair of lateral control -surfaces for use under other flight conditions, means for operating said* lateral. control surfaces to providenlateral vcontrol for said airplane and for transferring the lateral control function from one pair of lateral control surfaces to the other comprising, a manual control, a lever member control surfaces for use under certain flight conditions and a second pair of lateral control 6. In an airplane having vone pair of lateral.

surfaces for use under other flight conditions,

means for operating said lateral control surfaces and for transferring the lateral control function from one pair to the other comprising, a

manual control, a lever member tiltable by said manual control about a centrally disposed ilxed 'fulcrunu ai pair of movable blocks carried by said lever spaced apart substantially one-half the length of said lever, llnlrs connecting said blocks respectively with said pairs of control surfaces, anda screw shaft threaded through said blocks and rotatable under manual control to move said blocks along said lever-to change their position with respect to said ilxed iulcrum.

' 8. In an airplane, aset of ailerons for lateral control, a set of lift spoiler aps for lateral control, a single manually operable device for con` trolling both the ailerons andthe lift spoiler `aps, and a change-over mechanism for transferring the lateral control function. from said lift spoilers to said ailerons or vice-'versa and having in its operation a transitional period during which the ailerons and lift spoiler naps function together to provide lateral control for said airplane, said mechanism and said ailerons and lift spoiler naps being so constructed and arranged that there is no substantial diminution in ,the effectiveness of the lateral control during said transitional period.

9. In an airplane, two sets of movable lateral control surfaces, a single manually operableelement for effecting lateral control of said airplane, and e. mechanism fortransferring the lateral control function from one set of control sur` faces to the other, saidmechanism having in its operation a transitional range during which both sets of control surfaces are operative to provide lateral control for said airplane, said mechanism and said surfaces being so constructed and arranged that at any point in said transitional range when both sets of control surfaces are operative, the control action is substantially the same as when only one set of said surfaces is operative. l 10. In combination with an airplane and wing for supporting said airplane in flight,

ailerons operatively associated with said wing to provide lateral control for said airplane, lift spoilers operatively associated with said wing to provide lateral control for said airplane, means for decreasing the lateral control effectiveness of either of said lateral control devices While simul- `taneously'increasing the eectiveness of the alternative device substantially proportionately,

fit

and manually actuatable means for operating said lateral control devices.

11. In combination with an airplane and a wing for supporting said airplane in flight, means associated with said Wing operative to increase the lift thereof, lift spoilers operatively associated with said wing for providing lateral control for said airplane, and means for increasing the lateral control effectiveness of said lift spoilers as said lift increasing devices are put into operation.

12. 1n combination with an aircraft having a wing provided with lift increasing devices, a pair of manually operable lift spoilers associated with said wing to provide lateral control for said airplane, and means rendering said lift spoilers substantially inoperative exceptwhen said lift increasing devices are operative to increase the lift of said wing.

i3. In combination with an aircraft having a. sustaining wing, ailerons and lift spoilers operatively associated with said Wing for lateral control of said airplane, means operative to de crease the lateral control eiectiveness of said ailerons, and means for increasing the lateral control effectiveness of said lift spoilers as the effectiveness of said aileronsis lost.

14. In combination with an airplane and a sustaining wing therefor, a set of lateral control devices designed for use under high-speed flight conditions operatively associated with said wings, a second set of lateral control devices designed for use under slow speed flight conditions also operatively associated with said wing, pilot actu'- ated means for operating both sets of devices and means operative to progressively transfer the lateral control function from one set of lateral control devices to the other.

15. In combination `with an airplane and a wing -for supporting said airplane in ilight, ailerons operatively associated with said wing to provide lateral control for said airplane, lift spoilers operatively associated with said wing to provide lateral control for said airplane, means for changing the function of said ailerons from said lateral control function to a wing lift coeiiiclent increasing function, and means for increasing the lateral control effect of said lift spoilers as the lateral control eiiect of said ailerons decreases.

16. In combination with an airplane and a wing for supporting said airplane in flight, ailerons operatively associated with said wing to provide lateral control for said airplane. lift spoilers operatively associated with said wing to provide lateral control for said airplane, means for changing the function of said ailerons from said lateral control function to a wing lift coeflicient increasing function, and means for increasing the lateral control effect of said lift spoilers as the lift coefficient increasing effect of said ailerons progresses.

17. In an airplane having selectively useable groups of ight control instrumentalities, common means for operating both said groups of flight control instrumentalities, and means for gradually shifting the flight control function from one group to another of said instrumentalities having in its operation a transitional range during which both groups of control instrumentalities are operative, said means and said instrumentalities bring so constructed and arranged that at any point in said transitional range when both groups o'f control instrumentalities are operative the control action is substantially the same as when only one group of said instrumentalities is operative.

18. In an airplane, in combination, ailerons having means for drooping the same to increase the lift of the airplane, means for moving said ailerons to control said airplane, lift spoilers,

means for moving said lift spoilers to control said airplane, and pilot controlled means connecting said aileron moving means and said lift spoiler moving means for selecting the control to be used and rendering the alternative control means substantially inoperative for control purposes, said means being constructed and arranged so that as the ailerons are drooped the proportion of control by the lift spoilers may be increased and the proportion of control by the ailerons may be decreased.

REX B. BEISEL.

PAUL S. BAKER. 

